Centralizer



Dec. l, 1953 H. A. GILLERsTRoM 2,661,189

CENTRALIZER Filed sept. 29, 1951 Y 2 Smeets-sheet 1 Dec. 1, 1953 H. A. GILLERsTRoM 2,661,189

INVENToR jflmerAGiZIerszfrom Patented Dec. 1, 1953 CENTRALIZER Hilmer A. Gillerstrom, Arcadia, Calif., assignor to Independent Pneumatic Tool Co., Aurora, Ill., a corporation of Delaware Application September 29, 1951, Serial No. 248,939

3 Claims.

i This invention relates to rock drilling machines in general and particularly to an improved form of guide means for drill steels which guides are commonly known as centralizera (Cl. Z55-51) to the accompanying drawings which form a. part of said specification and in which drawings:

Figure l is a side elevation of a typical portable rock drilling machine in which the present inven- In the drilling oi rock and like materials the tion is incorporated; drilled hole must be started in axial alignment Figure 2 is a top plan view of Figure l, partly with the drill steel and must thereafter be mainin Section 011 the staggered line 2-2 thereof to tained on that line to prevent the drill from dScOSe Darts Otherwise concealed from View; wandering ou at an angle with resultant diiiicul- Figure 3 is an enlarged front elevation of the ties in operation including bending and possible centralizer of the present invention, the area breaking or the drill steel or the chuck in which viewed being indicated by the arrowed lines 3-3 it is held, excessive consumption of power due of Figures 1 and 2; to bending of the drill steel and its frictional en- Figure 4 is a top plan view of Figure 3; gagement with the sides of the hole, and the Figure 5 is a fragmentary sectional view taken jamming of the drill steel in the hole with the on the line 5 5 of Figure 3; and attendant diliiculty of removal and the conse- Figure 6 is a fragmentary sectional view taken quent loss of productive time. at right angles to Figure 5 and indicated by the It is an object of the present invention to line 6 5 on Figure 4. provide a centraliser for rock drilling apparatus Referring to the drawings, the illustrated mawhich may be readily7 opened and closed about a 20 chine to which the invention is applied comdrill steel and which when closed will accurately prises a horizontally disposed U-shaped frame hold the drill in proper axial alignment with the member I having a pair of main wheels 2 atdriving motor so that the hole will be accurately tached to the ends of the legs 3 of the frame and started and maintained in alignment. a dirigible caster wheel Li attached to the center Another object of the invention is to provide a of the closed end of the frame. Clamped to device of the above character which may be op* each leg portion 3 near the closed end of the erated by the operator or by the forward move frame and extending upwardly therefrom are ment of the drill itself, and which in a preferred bracket elements 5 having oppositely disposed form may be operated by the foot of the operator bearings 6 in which the ends of the legs 'l of a so that it can be opened Without the necessity U-shaped support 8 are pivotally mounted. Each of the operator manually releasing the throttle leg portion 'l at about its mid-length carries a control of the drill operating motor. clamp collar S having depending ear portions con- A further object or" the invention is to provide nected by bolts l0, and the bolts Iii between the a. rock drill centralizar in which the bearing surclamp collar ear portions also pivotally support faces between relatively moving parts are comone end of internally threaded sleeves Il the oppletely enclosed and protected against the enpOSle ends 0f Which are threadedly engaged by trance of injurious dust and chips and the like. adjusting screws l2 nii/Otani mclmted 111 bear- Still another object of the invention is to proings I3 at the 10W1`- el'lfs 0f .the backets 5, 5 vide a centralizer -ior rock drilling apparatus in and geared for, rotato'n m mlson by a Shaft l@ which all relatively moving parts are spring biased 40 also mmfnted m bearmgs in the brackets 5 5 to prevent vibration and rattling as the parts beand ope; ated by anyfmtbe means Such as the come Worn crank I5. As the auJusting screws are rotated with resultant extension or contraction of the .A Stm furthe? obJeCt of the lnx/.minou 1S to p10' combined length of the sleeves I l and screws Wd? 32 celltrahzr for rock, drlumg apparatus 45 l2 the angular position of the U-shaped support Whlch 1s smfple m collstructlon 1S composed of 8 Will be varied with consequent raising and lowfew parts, is economical to manufacture, and erng of the closed end thereof' pivotal, Which is reliable and efficient in u=5emounted on the closed end of the member 3 with With the foregoing Objects in View, tOgetl'lcl" provision for being secured in adjusted angular with such other Objects and advantages as may position thereon, including the clamping plate Subsequently appear, the invention resides in the IS and bolts il, is a mast assembly i8 including parts, and in the construction, combination, and spaced parallel rails i8 and 2c held in spaced arrangement of parts, disclosed by way of examrelation at their upper end by a mast crown ple, in the following speciiication of one mode of plate 2l and at their lower end by a cross-bar execution of the invention, reference being had 22. Slidingly mounted on the rails is a drill motor 23 movable therealong by power operated means including a sprocket chain 24 trained over sprockets at the upper and lower ends of the mast assembly. The motor 23 includes a chuck 25 adapted to receive the ends of drills such as shown at 26 and imparts both impact and rotation to the drills as is common in drilling rock or the like. The above described portable frame structure and adjustable mast supporting means forms no part of the present invention and have been described merely by way of providing a better understanding of the purpose of and mode of operation of the invention.

Mounted on the outer faces of the rails I9 and 20, respectively, at the lower ends thereof and secured thereto by bolts 21 are brackets 28 and 29 each having 'a transverse boi'e 30 extending therethrough parallel to the face of the rail to which the bracket is attached and perpendicular with respect to the axis of the drill 23, each of said bores at the end thereof remote from the drill being coaxially enlarged, as at 3|, to house a compression spring 32 to be later referred to in more detail. Additionally, each bracket 28 and 29 on the side thereof opposite the lower end of the mast assembly is provided with a, bore 33 which intersects the bore 30 at its inner end and is threaded at its outer end to threadedly receive a plug 34. The drill engaging and centralizing elements of the invention comprise swinging arm members 35 and 35 having shank portions 31 and 38, respectively, which are journaled in the bores 3D of the brackets 2B and 29 (see Figure 4) and include shoulder portions 38 and 39 which engage the ends of the brackets adjacent the drill and reduced diameter portions 40 which extend through the enlarged bores 3| and the springs 32 therein and terminate in threaded ends 4| beyond the brackets which threaded ends are engaged by nuts 42 with washers 43 interposed between the nut and the face of the bracket completely enclosing the bearing surface, while the springs 32, being compressed in the enlarged bore, supply a frictional bias to resist unintentional rotative movement of the arms 35 and 36 in the brackets 28 and 23.

Each of the shank portions 31 and 38 is provided with a pair of parallel longitudinally extending grooves 44 and 45 which are engageable by spring biased detents 45 mounted in the bores 33 in the brackets 2B and 29 and yieldingly urged toward the grooves by compression springs 41 compressed between the inner ends of the plugs 34 and the outer ends of the detent elements 45 (see Figures and 6). The side walls of the grooves 45. and 45 are inclined and the groove engaging faces of the detents are correspondingly inclined so that upon the application of sufficient turning effort on the shank the detent will be raised out of the groove with which it is engaged and 4allow the shank to be turned. Normally, the pressure exerted by the springs 41 is sufficient to hold the shank in either of the two positions determined by the location of the grooves 44 and 45. It is to be noted that the above described detent construction is also enclosed to prevent the intrusion of rock dust or muck or other deleterious matter.

The shanks 31 and 38, respectively, carry outwardly extending and converging arms 35 and 36 which terminate in opposed semi-circular drill eng-aging faces 50 and 5| generated about the axial line of the drill chuck, the end faces 53 and 54 of the arms being slightly separated from each other (see Figure 4). Referring to Figure 3, the arms 35 and 36 are shown in drill engaging and centering position and it is to be noted that the end faces 55 and 56 of the drill engaging faces toward the drill chuck are so disposed that a plane P containing the axes of the shanks 31 and 38 passes between the drill chuck and the faces 55 and 56. Consequently, as the arms 35 and 36 are swung out of drill engaging position, all portions thereof will be moving away from the drill and thus, by the novel expedient of the selection of the proper location of the bearing for the drill engaging arms a simplified construction is achieved. Additionally, it is to be noted that in the event that the drilling progresses to an extent that the end of the drill chuck encounters the faces 55 and 56, the only effect will be that the arms 35 and 36 will be swung about their pivotal mounting and thus preclude the possibility of damage to the drill rig. The groove 44 in each of the shanks 31 and 38 is so located that when engaged by the detent 46, the arms are in drill engaging position while the grooves 45 are located approximately degrees from the grooves 44 so that when engaged by the detents 46, the arms 35 and 36 are substantially at right angles to their drill engaging position and afford clearance for the advancing drill motor to pass between them. Each of the arms 35 and 36 is further provided with an outwardly extending lug portion 51 adjacent the drill engaging face thereof to facilitate manual operation thereof. When drilling a vertical or nearly vertical hole the driller can move the arms 35 and 36 out of drill engaging position by stepping on the lugs 51 and without necessity for releasing the manual control of the motor throttle or the feed control with the resultant stoppage of the drilling operation.

From the foregoing it will be realized that there has been created a centralizing means for rock drilling machines which is simple in construction and which is composed of parts of simple design fand susceptible of economical manufacture. The device, further, is so designed that accidental engagement between the drill motor and the device will merely disengage it from the drill guiding function without damage to the motor or the other parts of the rig. Other advantages will be `apparent to those skilled in the art.

While in the foregoing specification I have described and illustrated a specific embodiment of my invention by way of example, the invention is not to be understood to be limited to the speciiic form thereof so disclosed and it includes in its scope all such modifications in the parts, and in the construction, combination and arrangement of parts as shall come within the purvie of the appended claims.

I claim:

1. A drill centralizer for use with a drilling apparatus of the type having a pair of spaced rails disposed in a common plane and paralle1 to each other, a drill motor mounted on said rails, and a drill steel driven by said motor and extending parallel to said rails for engagement with the substance to be drilled, said drill steel being d1s'posed approximately midway between said rails but being displaced a substantial distance from said common plane of said rails; which comprises a pair of brackets having corresponding cylindrical bores therein and mounted one -on each of said rails adjacent the point of drillmg, the axes of said bores being perpendicular to said common plane of said rails and being disposed in a transverse plane which is perpendicular to said drill steel and to said rails, a pair of arms respectively journalled at their inner ends in said bores and converging toward said drill steel to form at the outer ends thereof compleu mentary end faces, said end faces being canted relative to said arms to engage and guide opposite portions of said drill steel when said end faces are disposed wholly on the side of said transverse plane which is remote from said drill motor, and means to hold said arms in guiding position at which said end faces are disposed wholly on said side of said transverse plane remote from said drill motor.

2. A drill centralizer for use with a drilling apparatus having a pair of spaced rails disposed in a common plane and parallel to each other, a drill motor mounted on said rails, and a drill steel driven by said motor and extending parallel to said rails for engagement with the substance to be drilled, said drill steel being disposed approximately midway between said rails but being displaced a substantial distance from said common plane of said rails; which comprises a pair of brackets having` corresponding cylindrical bores therein and mounted one on each of said rails adjacent the point of drilling, the axes of said bores being perpendicular to said common plane of said rails and being disposed in a transverse plane which is perpendicular to said drill steel and to said rails, a pair of arms respectively journalled at their inner ends in said bores and converging toward said drill steel to form at the outer ends thereof complementary end faces, said end faces being canted relative to said arms to engage and guide opposite portions of said drill steel when said end faces are disposed wholly on the side of said transverse plane which is remote from said drill motor, and spring biased detents mounted, respectively, in said brackets and adapted to ride into radially spaced longitudinal grooves in said inner ends of said arms, said detents and grooves being disposed to hold said arms in guiding position at which said end faces are disposed wholly on said side of said transverse plane remote from said drill motor.

3. A drill centralizer for use with a drilling apparatus having a pair of spaced rails disposed in a common plane and parallel to each other, a drill motor mounted on said rails, and a drill steel driven by said motor and extending parallel to said rails for engagement with the substance to be drilled, said drill steel being disposed approximately midway between said rails but being displaced a substantial distance from said common plane of said rails; which comprises a pair of brackets having corresponding cylindrical bores therein and mounted one on each of said rails adjacent the point of drilling, the axes of said bores being perpendicular to said common plane of said rails and being disposed in a transverse plane which is perpendicular to said drill steel and to said rails, a pair of arms respectively journalled at their inner ends in said bores and converging toward said drill steel, a pair of end faces provided at the outer ends of said arms and canted relative thereto to guidingly engage opposite portions of said drill steel at points wholly on the side of said transverse plane remote from said drill motor, said bores in each of said brackets at the ends thereof remote from said drill steel being enlarged and the corresponding cylindrical inner ends of said arms being reduced in diameter and terminating in threaded end portions extending beyond said brackets, a shoulder portion on each arm engaging the end face of the corresponding bracket relatively adjacent said drill steel, a nut threaded on said end portion of each arm, a helical compression spring mounted in said enlarged portion of each bore to urge the corresponding arm shoulder portion into snug engagement with the associated bracket end face, and detent means to hold said arms in guiding position at which said end faces are disposed wholly on said side of said transverse plane remote from said drill motor.

I-HLMER A. GILLERSTROM.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,055,520 Curtis Sept. 29, 1936 2,108,035 Fuehrer et al. Feb. 15, 1938 2,244,127 Smith, Jr June 3, 1941 2,274,698 Feucht et al. Mar. 3, 1942 2,308,203 OFarrell Jan. 12, 1943 2,357,001 Hope Aug. 29, 1944 2,365,686 Osgood Dec. 26, 1944 2,523,512 Nast Sept. 26, 1950 2,540,574 Feucht Feb. 6, 1951 

